Thermostat.



H. D. SINGER 81H. V. D. PRATT.

THERMOSTAT.

APPLICATION FILED $1213.11, 1911.

Patented 31111.12, 1915.

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Specification of Letters Patent. Patented Jam, 12, 31915,

Application filed September 11,1911. Serial No. 648,648.

To all whom, it may concern:

Be it known that we, HAROLD D. SINGER and HOWARD V. D. PRATT, a subjectof the Kingof Great Britain and a citizen of the United States,respectively, residing at Hospital, in the county of Kankakee and Stateof Illinois, have invented a new and useful Improvement in Thermostats,of which the following is a specification.

Our invention relates to improvements in thermostats of the typeinvolving a thermometer-tube having one of the electric terminalsconnected with the mercury therein and the other of the electricterminals adjustable in the tube to make contact with the upper end ofthecolumn of mercury to close the circuit when the mercury rises in thetube to a predetermined point.

@ur object is to provide a novel and simple construction of thermostatof the type above referred to, and-to provide for the maintenance of thevacuum in the tube at all times regardless of the adjustment of theupper electric terminal therein.

Referring to the accompanying drawings:

Figure 1 is a view in elevation of our improved thermostat shownextending into a tank illustrated in section, the contents of which areto be maintained at a predetermined temperature; and Fig. 2, an enlargedsection taken at the line 2 on Fig. 1 andviewed in the direction of thearrow.

1n the drawings we have illustrated our improved thermostat as themedium for at controlling the making and breaking of electric circuitsbetween a source of electrical energy (not shown),-and mechanism (notshown) for controlling the supply of a heating medium to the tankrepresented'at- 4, and into which our improved thermostat extends.Rising is an upright 5 provided with an arm 6 through athreaded opening7 in which a threaded rod 25 extends. The lower. end of this rod isrigidly connected with a magnet 24, shown as a permanent magnet ofhorse-shoe form, though an electro-magnet may be substituted therefor ifdesired, the upper end of the rod 25 carrying a thumbpiece 26 by meansof which the rod 25 and the magnet 2 1 may be rotated, the rod25 and themagnet raising or lowering when the rod is turned, depending upon thedirection in which it is rotated. The thermometer tube, which extendsinto the tankand is secured thereto in any desirable manner,";

from the top of the tank.

as by means of a clip 13 secured to a wall of the tank, is illustratedat 1 1, it being preferred that this tube be of the form shown, namely,with upper and lower expanded tubular sections 15 and 16, respectively,and a restricted intermediate capillary section 17, the mercury -orother expansible fluid employed, and represented at 18, filling thetube-section 16 and extending upwardly into the section 17, a vacuumbeing provided in the tube above the mercury. An electric terminal wire19 extends through a wall of the tube 14, in which it is sealed, intocontact with the fluid 18 and the other electric terminal 20 extendsthrough and is sealed in the top of the tube-section 15. The terminal 20is connected with a member 30 confined in the tube-section 15, thismember being formed of a cross-piece 31 and depending sections 32 ofspring metal which latter press against the inner walls of thetube-section 15 and prevent the member 30 from turning when the deviceis operated, as hereinafter described. Depending from and rigidlysecured in the cross-piece 31 is a threaded rod 29 which hasscrew-thread engagement with a member 28 of soft iron, forming anarmature for the magnet 24.

The armature 28 carries on its under side a depending yoke. 33 which iselectrically connected with the upper end of a depending contact wire23, preferably of platinum,

which extends downwardly into the upper endof the tube-section 17 and.operates to make electrical contactwith the mercury 18.,

when the latter rises into contact therewith. The operation oftheapparatus illus trated is as follows: When the temperature wof-thewater-in the tank 4 reaches a predetermined degree, dependlngupon theheight at whichthe lower end of the contact 23 extends in thetube-section 14, the mercury 18, in ascending in the tube contacts withthe lower end of the wire 23, thus establishing an electrical circuitbetween the termi-' nal 20 and fluid 18 through the wire 23, yoke 33,armature 28, rod 29 and cross-piece 31, which, in practice, wouldoperate to close a circuit for controlling the operation of mechanism(not shown) for shutting off the supply of heat medium to the tank/i. Byturning the rod 25 the magnet 24 is rotated and caused to travel up ordown, depending on' the direction in which this rod is rotated, themagnetic force exerted by the magnet on the armature 28, causing thelatter to turn, with the magnet, on the threaded rod 29, the latter, bypreference,

. having the'same size thread as that on the Y rod 25, and thusadjusting theilower end of 5 the wire contact 23 with relation to thetop of the fluid 18. It will be understood that by rotating the magnetas described, the position occupied by the wire 23 relatiy'eto ..0 tionWith a tank for containing Water, the

to be controlled,

temperature of which is our improved device is not limited in its use tosuch apparatus, as it may be used in any situation Where the employmentof 25 a thermostat of this "general type is desirable.

What we claim as new, and desire to secure by Letters Patent, is V '1.In a thermostat-device, the combination of a thermometer-tube containingan expansible fluid, a member in said tube pro vided with spring-armsbearing against the inner wall of the tube, netizable material in saidtube'and having screw-threaded connection withsaid firstnamed member andmovable up and down relative thereto, and electric-circuit terminals oneof which is in contact with said fluid and the other of which issupported 40 by said member of magnetizable material relative to theupper end of the fluid. I 1 2. In a thermostat-device, the combinationof a thermometer-tube containing an expansible fluid, spiralguiding-means in a rotatable member of magnetizv able material engagingwith said guidingsaid tube,

a member of magmeans, electriccircuit terminals one of WhlCh 1s 1ncontact with said fluid and the other of which is supported by saidmember relative to the upper end of the fluid,

said tube, a rotatable member of magnetizable material engaging withsaid guidingmeans, I electric-circuit terminals one of which 'is incontact with said fluid and the other of which is supported by saidmember relative to the upper end of the fluid, a support, spiralguiding-means on said support having the same pitch as said firstnamedguiding-means, and a rotatable magnet external. of the tube cooperatingwith 4 said member of magnetizable material and engaging with saidlast-named guiding means, for the purpose, set forth.

4. In a thermostat-device, the combination of a thermometer-tubecontaining an expansible fluid, spiral guiding-means in said tube, arotatable member of magnetizable material engaging with saidguidingmeans, electric-circuit terminals one of which is incontact Withsaid fluid and the other of which is supported by said member sorelative to the upper end of the fluid, a support, and a rotatablemagnet external of the tube, coiperating with said member ofmagnetizable material and provided wlth a stem having screw-threadedconnection with said support, for the purpose set forth.

\ HAROLD D. SINGER.

HOWARD V. D. PRATT.-

In the presence of-.-

. A. U. 'THORIEN, v R. A. SCHAEFFER.

